Various types of liquid cleaning apparatus are used to clean printed circuit boards for removal of contaminates, such as flux residues, resins and the like. These contaminates remain on the printed circuit board from the soldering process. Many liquid cleaning apparatus include a series of processing chambers, each dedicated to a specific phase of the cleaning process, through which the printed circuit boards pass. Often, a conveyor system including a conveyor belt is used to move the printed circuit boards through the various chambers.
The cleaning materials used for cleaning the printed circuit boards may be determined primarily by the flux technology. For example, water-soluble organic acids may require water only for removal from the printed circuit board and rosin flux technology may require a solvent, semi-aqueous or aqueous cleaning material for removal from the printed circuit board.
Along with the type of cleaning medium, it is also believed that spray geometry during the cleaning process can play an important role in contaminant removal. U.S. Pat. No. 5,129,956, for example, discloses use of a helically-vaned nozzle that produces a cone-shaped spray stream of highly atomized droplets. These highly atomized droplets, however, have a limited amount of energy that can be applied to the printed circuit board on impact.